The EMBO Journal, 11 (4). pp. 1543-1551.
The signal recognition particle (SRP) binds to signal sequences when they emerge from a translating ribosome and targets the complex of ribosome, nascent chain and SRP to the membrane of the rough endoplasmic reticulum (rER) allowing the co-translational translocation of the nascent chain. By photo-crosslinking it has been shown that the signal sequence of preprolactin(PPL) only interacts with the methionine-rich (NI) domain of the 54 kDa protein subunit (SRP54) of SRP. Here we show that (i) a signal-anchor sequence is likewise crosslinked only to the methionine-rich domain of SRP54,(ii) free SRP54 can interact with signal sequences independently of the other components of SRP, (iii) its M domain suffices to perform this function, and (iv) an essentially intact M domain is required for signal sequence recognition. Alkylation of the N+G domain in intact SRP54 with N-ethyl maleimide (NE), but not after cleavage with V8 protease, prevents the binding of a signal sequence to the M domain. This suggests a proximity between the N+G and M domains of SRP54 and raises the possibility that the role of the N+G domain may be to regulate the binding and/or the release of signal sequences.
|Journal or Publication Title:||The EMBO Journal|
|Page Range:||pp. 1543-1551|
|Faculties / Institutes:||Service facilities > Center for Molecular Biology Heidelberg|
|Subjects:||570 Life sciences|
|Uncontrolled Keywords:||GTP binding protein , methionine-rich domain of SRP54 , photo-crosslinking , signal sequence binding , signal recognition particle|
|Schriftenreihe ID:||Works by Bernhard Dobberstein|